Loss of energy and lack of physical ability are two major but largely obscure effects of cancer and cancer treatments. Cancer survivors often simply accept the extreme tiredness and inability to lift their limbs as part of an already high price paid to combat the disease. It has been estimated that 70 percent of cancer patients experience such fatigue, nearly half of these suffering loss of energy for years after treatment is over.

Prescribing rest and a lower level of activity, well-meaning physicians may unwittingly perpetuate fatigue. No evidence exists that vigorous exertion is harmful, and a recent study published in ACSM's Medicine & Science in Sports & Exercise� (MSSE) suggests that carefully monitored exercise may be beneficial to cancer patients by reducing fatigue and improving the ability to complete activities of daily living.

Researchers from Freiburg University Medical Center in Freiburg, Germany set out to document the effects of an aerobic training program on cancer patients, testing the hypothesis that exercise would improve the energy level of the afflicted individuals. The results of their study are published in the April, 1998 issue of MSSE. They recruited patients ranging in age from 18 to 55 years. All of the patients had been suffering fatigue for at least five weeks, some for as long as 18 months.

The subjects, four women and one man, found themselves unable to carry out normal daily activities. In fact, one subject had been forced by her extreme fatigue to leave school. Others in the study often felt the tiredness to be overwhelming. They could neither climb stairs nor perform the normal tasks associated with housekeeping.

The research team first assessed each patient's performance level with a treadmill test, then prescribed a regimen of treadmill walking for six weeks, five days a week, increasing the speed when the patient's body indicated (through monitoring of heart rate and blood lactate concentration) that it needed a higher level of activity in order to maintain consistent training intensity. Starting out at an average speed of 5 Km/hr (3mph) for three minutes at a time, then at half speed or sitting to recover, the patients' regimen was changed slowly until eventually they were training for 30 to 35 minutes without finding it necessary to rest.

The results were consistent in all five subjects. All parameters of physical performance substantially improved. Study participants were able to extend the time they exercised without fatigue, as noted above. Heart rate decreased at an average from 138 beats per minute (bpm) to 113, and blood lactate concentration decreased significantly.